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Author Topic: l298 89v51 interface  (Read 1608 times)

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Offline krjariwalaTopic starter

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l298 89v51 interface
« on: March 28, 2010, 12:32:20 AM »
hi,
i m facing the problem of loading when i interface l298 with port 0 of 89v51 with 4.7k pullup.when i connect the logic pins of l298 the port pin shows an output of 1.65 volts else its 5V which is correct. what changes should i do?

Offline Soeren

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Re: l298 89v51 interface
« Reply #1 on: March 28, 2010, 09:42:54 AM »
Hi,

i m facing the problem of loading when i interface l298 with port 0 of 89v51 with 4.7k pullup.
Why the pull-up?


when i connect the logic pins of l298 the port pin shows an output of 1.65 volts else its 5V which is correct. what changes should i do?


Which pins do you connect to?

With a max. load current of 100A for a "High" input and a max. load current of 10A for a "Low" input, even if the controller tries to pull low, the 4k7 pull-up will be the largest load with up to a theoretical 1mA (i.e. 100 times rhat of the L298).

So, something is clearly wrong!
Either you connected it up wrong or the controller or the L298 is shot.
Regards,
Sren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline waltr

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Re: l298 89v51 interface
« Reply #2 on: March 28, 2010, 10:42:24 AM »
Or the port is set-up as an input not an output.

Offline krjariwalaTopic starter

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Re: l298 89v51 interface
« Reply #3 on: March 28, 2010, 11:08:12 PM »
i need pullups on port 1 ,0 and 2. i am using port 0.1 nad 0.2. also i tried on port 3 where there are no pull ups on p3.1 nad 3.2.
same problem occurs.

Offline krjariwalaTopic starter

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Re: l298 89v51 interface
« Reply #4 on: March 29, 2010, 01:25:28 AM »
one thing i have found  is its working on channel 2 but  not on channel 1. why does this happen?

Offline Soeren

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Re: l298 89v51 interface
« Reply #5 on: March 29, 2010, 02:10:52 AM »
Hi,

Sounds like waltr was right, you are using the port as input.
Output ports don't need pullups.
Change the direction register and the problem should go away.

I'd recommend reading up on microcontrollers, perhaps read and follow a few beginners tutorials to get the gist of it.
Regards,
Sren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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